The present invention relates to a sleeping bag and more particularly to a sleeping bag which is used within or outside a camping tent for outdoor activities.
The conventionally used sleeping bag for camping purposes is composed of a mattress portion and a coverlet portion, said mattress portion and said coverlet portion being joined to each other at one side thereof while the inside of the sleeping bag is stuffed with cotton paddings or the like. Along the other sides and foot ends of said mattress portion and those of said coverlet portion are attached slide fasteners for closing said sleeping bag with the coverlet portion being laid over the mattress portion like an envelope.
Said conventional sleeping bag has a problem is that the camper fails to get sound sleep when used on undulations of the camping ground. Therefore, the camper is forced to extend an air mattress or other cushioning materials beneath the sleeping bag or place an air pillow at a head portion thereof.
However, even if an air mattress or the like is used in the manner mentioned above, the conventional sleeping bag has the following problems:
1) the sleeping bag fails to give the camper a sound sleep on account of its general tendency to slip off the air mattress or the air pillow's slipping off the sleeping bag; PA1 2) the camper must use such a large sized air mattress so as to prevent the sleeping bag from slipping off it that a space economy is neglected; and PA1 3) if a sheet material is selected to be used beneath the sleeping bag, comfortable sleep is not enjoyed where there are undulations at a camping site because such sheet material lacks cushioning functions and it is impossible to block the cold from beneath particularly on the snow-clad ground so that many insulating layers must be used to make up for such drawback.